Can you provide me with the full command that is failing? I have numerous plugins that are still working that pass some kind of CSS to mdpopups, so it isn't something that is fundamentally broken, but something specific, so I'll need a specific example. Also provide Color Scheme as that may play into this.

It's PackagesUI but my version with phantoms. Other plugins where I use popups are the same, though. Changing the scheme to Mariana doesn't change anything(getting default popup background, not injected css).

A lot of the underlying libraries got changed, and so some things got missed in my testing. I assume you are on Sublime < 3150. I should have run this through a portable Python of the most recent official release before pushing the new version. Oh well.

Also I have to say that with 3.0.0 ColorHelper didn't show the color squares anymore while editing color schemes, rolling back mdpopups to two commits before fixed this too, so it also depended on the new version.

3.0.2

3.2.0

Nov 21, 2017

NEW: pymdownx and pyyaml are now required for use of mdpopups (#51).

NEW: Add support for .hidden-color-scheme (#50).

It was mentioned back in June that packages that depend on mdpopups need to update dependencies accordingly, so if you haven't already done so, you make get issues filed on your repo about pyyaml or pymdownx not being found.

Thinking about it now, probably should have called this 4.0.0 due to the breaking change, but too late now.